5 Biological role
5.2 Non-coding RNA or "RNA genes" ... role
RNA plays several roles in biology:
RNA ( mRNA ) is transcribed directly ( splicing ... tRNA paits with the codon of on the mRNA
Main article: ...
... referred to as a "signalling cascade " or "second messenger
pathway" and the result is that a small stimulus ... signal transduction
5.1 Ca2+ as a second messenger
5.1.1 Activation of Ca2+
5.1.2 Function of Ca2+
5.2 Lipophilic second messenger
5.3 Nitric oxide (NO) as ...
... ATPase, which can operate at lower intracellular concentrations of calcium and sets the normal or resting concentration of this important second messenger
. But the ATPase exports calcium ions more slowly: only 30 per second versus 2000 per second by the exchanger. The exchanger comes into service when ...
Nobel Prize in Physiology or Medicine
SI derived unit
Some pictures ...
... three-letter 'words' (termed a codon ) formed from a sequence of three nucleotides (e.g. ACT, CAG, TTT). These codons can then be translated with messenger
RNA and then transfer RNA, with a codon corresponding to a particular amino acid. Since there are 64 possible codons, most amino acids have more ...
A hormone (from Greek horman - "to set in motion") is a chemical messenger
from one cell (or group of cells) to another. All multicellular organisms (including plants ) produce hormones. The best known hormones are ...
Major histocompatibility complex
... cell is almost always apoptosis , or programmed cell death, initiated by the CD8+ T cell. This response seems like "killing the messenger," but the messenger
in this case is virally infected and probably represents a risk of contagion for neighboring cells.
Mhc Class II molecules are found only on a ...
... acid takes over and uses the host cells organelles to make many copies of the virus. In the case of DNA viruses, the DNA transcribes itself into messenger
RNA (mRNA) molecules that are then used to direct the ribosome. In retroviruses , or RNA viruses, a unique enzyme called reverse transcriptase ...
... ligand-gated ion channels that open or close through neurotransmitter binding. Metabotropic receptor effects on ion channels are carried by second messenger
Neuroactive peptides are synthesized in the neuron's soma and are transported through the axon to the synapse. They are usually ...
... is a group of genes including an operator , a common promoter , and one or more structural genes that are controlled as a unit to produce messenger
RNA (mRNA). Operons occur primarily in prokaryotes and nematodes .
They were first described by Franois Jacob and Jacques Monod in 1961 .
Polymerase chain reaction
... into which DNA is transcribed prior to making a protein, and those strands of RNA that hold the instructions for protein sequence are known as messenger
RNA (mRNA). Once RNA is isolated it can be reverse transcribed back into DNA (complementary DNA to be precise, known as cDNA), at which point ...
... of the sieve-tube elements, producing the exactly opposite effect.
Organic molecules such as sugars, amino acids , certain hormones , and even messenger
RNAs are transported in the phloem through sieve tube elements .
Phloem is produced in phases. Primary phloem is laid down by the apical ...
... by RNA polymerase , which then initiates transcription. In RNA synthesis, promoters are a means to demarcate which genes should be used for messenger
RNA creation - and, by extension, control which proteins the cell manufactures.
The perfect promoter is called a canonical sequence .
... complex) a simple alternative for gene knockdown is Morpholino antisense oligos. While RNAi acts by directing cellular systems to degrade target messenger
RNA (mRNA), Morpholinos bind and block access to the target mRNA without requiring the activity of cellular proteins and without necessarily ...
... that was received by a
transmembrane receptor and pre-processed by other membrane-associated proteins . There are three basic types of second messenger
Hydrophobic molecules like diacylglycerol and phosphatidylinositols are membrane-associated and diffuse from the plasma ...
... important ways are phosphorylation and internalization (see ubiquitin ).